<!-- 
	This is the HTML file for the front-end of the AJAX Driven Chat application 
	This code was developed by Ryan Smith of 345 Technical Services
	
	You may use this code in your own projects as long as this copyright is left
	in place.  All code is provided AS-IS.
	This code is distributed in the hope that it will be useful,
 	but WITHOUT ANY WARRANTY; without even the implied warranty of
 	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
	
	For the rest of the code visit http://www.DynamicAJAX.com
	
	Copyright 2005 Ryan Smith / 345 Technical / 345 Group.
-->
<html>
	<head>
		<title>AJAX Driven Web Chat</title>
		<style type="text/css" media="screen">
			.chat_time {
				font-style: italic;
				font-size: 9px;
			}
		</style>
		<script language="JavaScript" type="text/javascript">
			var sendReq = getXmlHttpRequestObject();
			var receiveReq = getXmlHttpRequestObject();
			var lastMessage = 0;
			var mTimer;
			//Function for initializating the page.
			function startChat() {
				//Set the focus to the Message Box.
				document.getElementById('txt_message').focus();
				//Start Recieving Messages.
				getChatText();
			}		
			//Gets the browser specific XmlHttpRequest Object
			function getXmlHttpRequestObject() {
				if (window.XMLHttpRequest) {
					return new XMLHttpRequest();
				} else if(window.ActiveXObject) {
					return new ActiveXObject("Microsoft.XMLHTTP");
				} else {
					document.getElementById('p_status').innerHTML = 'Status: Cound not create XmlHttpRequest Object.  Consider upgrading your browser.';
				}
			}
			
			//Gets the current messages from the server
			function getChatText() {
				if (receiveReq.readyState == 4 || receiveReq.readyState == 0) {
					receiveReq.open("GET", 'getChat.php?chat=1&last=' + lastMessage, true);
					receiveReq.onreadystatechange = handleReceiveChat; 
					receiveReq.send(null);
				}			
			}
			//Add a message to the chat server.
			function sendChatText() {
				if(document.getElementById('txt_message').value == '') {
					alert("You have not entered a message");
					return;
				}
				if (sendReq.readyState == 4 || sendReq.readyState == 0) {
					sendReq.open("POST", 'getChat.php?chat=1&last=' + lastMessage, true);
					sendReq.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
					sendReq.onreadystatechange = handleSendChat; 
					var param = 'message=' + document.getElementById('txt_message').value;
					param += '&name=Ryan Smith';
					param += '&chat=1';
					sendReq.send(param);
					document.getElementById('txt_message').value = '';
				}							
			}
			//When our message has been sent, update our page.
			function handleSendChat() {
				//Clear out the existing timer so we don't have 
				//multiple timer instances running.
				clearInterval(mTimer);
				getChatText();
			}
			//Function for handling the return of chat text
			function handleReceiveChat() {
				if (receiveReq.readyState == 4) {
					var chat_div = document.getElementById('div_chat');
					var xmldoc = receiveReq.responseXML;
					var message_nodes = xmldoc.getElementsByTagName("message"); 
					var n_messages = message_nodes.length
					for (i = 0; i < n_messages; i++) {
						var user_node = message_nodes[i].getElementsByTagName("user");
						var text_node = message_nodes[i].getElementsByTagName("text");
						var time_node = message_nodes[i].getElementsByTagName("time");
						chat_div.innerHTML += user_node[0].firstChild.nodeValue + '&nbsp;';
						chat_div.innerHTML += '<font class="chat_time">' + time_node[0].firstChild.nodeValue + '</font><br />';
						chat_div.innerHTML += text_node[0].firstChild.nodeValue + '<br />';
						chat_div.scrollTop = chat_div.scrollHeight;
						lastMessage = (message_nodes[i].getAttribute('id'));
					}
					mTimer = setTimeout('getChatText();',2000); //Refresh our chat in 2 seconds
				}
			}
			//This functions handles when the user presses enter.  Instead of submitting the form, we
			//send a new message to the server and return false.
			function blockSubmit() {
				sendChatText();
				return false;
			}
			//This cleans out the database so we can start a new chat session.
			function resetChat() {
				if (sendReq.readyState == 4 || sendReq.readyState == 0) {
					sendReq.open("POST", 'getChat.php?chat=1&last=' + lastMessage, true);
					sendReq.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
					sendReq.onreadystatechange = handleResetChat; 
					var param = 'action=reset';
					sendReq.send(param);
					document.getElementById('txt_message').value = '';
				}							
			}
			//This function handles the response after the page has been refreshed.
			function handleResetChat() {
				document.getElementById('div_chat').innerHTML = '';
				getChatText();
			}	
		</script>
	</head>
	<body onload="javascript:startChat();">
		<h2><a href="http://www.dynamicAJAX.com" style="color: #000000; text-decoration: none;">AJAX Driven Web Chat</a></h2>
		<p id="p_status">Status: Normal</p>
		Current Chitter-Chatter:
		<div id="div_chat" style="height: 300px; width: 500px; overflow: auto; background-color: #CCCCCC; border: 1px solid #555555;">
			
		</div>
		<form id="frmmain" name="frmmain" onsubmit="return blockSubmit();">
			<input type="button" name="btn_get_chat" id="btn_get_chat" value="Refresh Chat" onclick="javascript:getChatText();" />
			<input type="button" name="btn_reset_chat" id="btn_reset_chat" value="Reset Chat" onclick="javascript:resetChat();" /><br />
			<input type="text" id="txt_message" name="txt_message" style="width: 447px;" />
			<input type="button" name="btn_send_chat" id="btn_send_chat" value="Send" onclick="javascript:sendChatText();" />
		</form>
	</body>
	
</html>